Photographic print-out material having a design thereon



June 15, 1937. J. c. VILLE 8 PHOTOGRAP HIC f'RINT-OUT TERIAL HAVING A DESIGN T HEREON Filed July gs, 1955 PRINT-Our Z50 061761705 wi l? OLOR MCKMlI/YO v ATTORNEYS.

Patented June 15, 1937.

UNITED STATES PATENT OFFICE rno'rocnmrmc PRINT-OUT MATERIAL HAVING A DESIGN THEREON Joseph C. Ville, Rochester, N. Y., assignor, by

mesne assignments, to Eastman Kodak Company, Jersey City, N. 1., a corporation of New Jersey Application July 26, 1935, Serial No. 33,348

, I 14 Claims. This invention relates to photography and more particularly to a sensitive paper on which the design becomes visible or invisible under the action 1 design on it with a solution of a desensitizer or a 3 of light.

I have discovered that highly sensitive printout paper may be used to indicate 'the action or the intensity of light by printing or forming a restrainer for the sensitive print-out compound.

Sensitive photographic emulsions in which a visible image is produced directly by the action of light are called print-out emulsions. They are ordinarily" prepared by precipitating a halide of silver in a colloidal medium by interaction of a solution of a soluble halide with a solution of a.

soluble compound of silver. v If the emulsion is sensitized with silver chloride, the silver chloride is usually precipitated in such a way that the final product contains an excess of soluble silver compound for example, silver nitrate, together with the silver salt of an organic acid and some of the free organic acid. These emulsions are not washed after the precipitation of the sensitive salt. A highly sensitive print-out paper which is suitable for the process of my invention is described in Patent No. 2,030,860, granted February 18, 1936, to George E. Falleson and Cyril J. Stand.

In theaccompanying drawing Fig, 1 is a flowsheet showing a plan view of a sensitive printout paper having a design formed-thereon the same color as the unexposed surface before and after exposure; 1

Fig. 2 is a flow-sheet showing a plan view of a sensitive print-out paper having a designformed thereon of a color darker than that of the unexposed surface,- before exposure, after partial exposure, and after complete exposure.

' In carrying out myinvention I form a design 'on the surface of the sensitive print-out emulsion with a desensitizing or restraining compound. Under an action of light the sensitive portion of the print-out surface darkens and the portion treated with the desensitizer or restrainer is unaflfected'by the action of the light. I may include trim with the solution of the desensitizing or restraining compound-but this is only for the purpose or increasingor decreasing the contrast between the sensitive and desensitized portions of the surface" and is not absolutely-essentiaL.

Among the desensitizers or restrainers which are particularly useful in forming the design on the surface of the print-out emulsion, are thiourea and substituted thioureas; other organic sulfur compounds; the thiosulfates, such as sodium thiosulfate and other alkaline thiosulfates; alkaline 1 exposed paper.

cyanides, such as sodium cyanide; alkaline thiocyanates such as potassium thiocyanate; alkaline halides such as potassium iodide and potassium bromide. ample, a dye such as tartrazine or a mixture of tartrazine and malachite green. The desensitizing solution may be made up as follows: 1

Dye .1 gram *Potassium bromide saturated solution, 100 cc.

Water 20 cc. 3

Any suitable dye may be used, for ex- 1 In one aspect of my invention the solution of dye and desensitizeror restrainer is made up so that the solution when printed, or otherwise placed on the sensitive paper in the form of a design. the design resulting when the solution is dried has the same color as the sensitive surface.

This may be easily accomplished by selecting a dye of the same shade as the surface of the un- When this paper is exposed to light for a few seconds the sensitive portion darkens and the desensitized design portion retains the original color. The design thereby becomes visible under the action of light. The appearance of the design takes place in a few seconds in moderate daylight when highly sensitized print-out paper is used. If the paper is held at a distance of about one foot from a 60 watt Mazda lamp, the

' image is clearly visible in' about 20 seconds.

Another way in which my invention may be design and the background merge, and the design becomes invisible. On further exposure the background continues to darken and the design once more becomes visible and is then a lighter color than the background. Paper treated in this way can be used to measure light intensity. The length of time required for the background and design to merge is dependent on the intensity of the light and is an extremely accurate way of measuring light intensity. The intensity of light may be measured more accurately with such paper than by comparing the darkening of print-out paper with paper of a standard shade placed beside it. 1

, 2 retains its original color and is readily apparent by reason of the contrast in color between it and the exposed background portion la.

In the modification shown in Fig. 2, in which the paper is used to measure the intensity of light, the design portion 3 is formed from a solution containing a dye of a darker shade than the unexposed surface I. On exposure of this material to light, the background portion I will darken in color and the design portion 3 will retain the same color so that after a short time, as shown at lb, the color of the background will be the same as that of the design, and the design and the background portions will appear to merge. n continued exposure of this material to light thebackground portion lb will further darken in color and there will again be a contrast between the background portion and the design portion of the paper as shown at lc. Because of the contrast between the design portion and the background portion, in the unexposed and overexposed condition, the intermediate exposure stage in which the design and the background portions merge is an extremely critical one and permits an accurate measurement of' the time of exposure.

I have referred to restraining and desensitizing compounds. It is to be understood that by restraining compounds" I mean those compounds which may not strictly be called dea sensitizers but which restrain the printing-out of the sensitive surface to such an extent that an image is formed very slowlyor not at all. It is evident, therefore, that desensitizers' are only powerful restrainers.

Other advantages and ways of employing sensitive paper treated in accordance with my invention will be readily apparent. The modifications describedabove are by way of example only and it is to be understood that my invention is limited only by the scope of the appended claims.

What I claim is new and desire to secure by Letters Patent of the United States is:

1. A light-sensitive silver salt print-out surface having a design formed thereon with a solution of a colored compound and a chemical restrainer for the printing out of the light-sensitive compound.

2. A light-sensitive silver salt print-out surface having a design formed thereon with a solution of a dye and a chemical restrainer for the printing-out of the light-sensitive compound.

3. A light-sensitive silver salt print-out paper having a design formed thereon with a solution of a dye and a chemical restrainer for the print ing out of the light-sensitive compound.

4. A light-sensitive silver salt print-out surface having a design formed thereon with a solution of a compound of the same color as the unexposed print-out surface and a chemical restrainer for the printing-out of the light-sensitive compound.

5. A light-sensitive silver salt print-out surface having a design formed thereon with a solution of a dye of the same color as the unexposed printout surface and a chemical restrainer for the printing-out of the light-sensitive compound.

' 6. A light-sensitive silver salt print-out surface having a design formed thereon with a soluface having a design formed thereon with a solu tion of a compound of the same color as the unexposed print-out surface and potassium iodide.

10. The method of making a light-sensitive photographic material which comprises forming a design on alight-sensitive silver salt print-out surface with a solution of a dye of the same color as the unexposed print-out surface and a chemical restrainer for the printing-out of the lightsensi'tive compound.

11. The method of making a light-sensitive photographic material which comprises forming a design on a light-sensitive silver salt print-out surface with a solution of a dye of the same color as the unexposed print-out surface and thiourea.

12. The method of v making a light-sensitive photographic material which comprises forming a designon a light-sensitive silver salt print-out surface with a solution of a dye of the same color as the unexposed print-out surface and potassium iodide.

13. A light-sensitive silver salt print-out. surface having a design formed thereon with a solution of a colored compound and a desensitizer for the light-sensitive compound. a

14. A light-sensitive silver salt print-out paper having a design formed thereon with a solution of a dye and a desensitizer for the light-sensitive compound.

JOSEPH C. VII-LE. 

